package com.qinglei.recoup.app.util;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import net.sf.json.JSONObject;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.security.AlgorithmParameters;
import java.security.Security;
import java.util.Arrays;

/**
 * @ClassName WXDecryptUtil
 * @Description TODO
 * @Date 2020/11/24
 * @Author XiaoWeng
 * @Version v1.0.0
 */
public class WXDecryptUtil {
    public static JSONObject getUserInfo(String encryptedData, String sessionKey, String iv){
        // 被加密的数据
        byte[] dataByte = Base64.decode(encryptedData);
        // 加密秘钥
        byte[] keyByte = Base64.decode(sessionKey);
        // 偏移量
        byte[] ivByte = Base64.decode(iv);

        try {
            // 如果密钥不足16位，那么就补足.  这个if 中的内容很重要
            int base = 16;
            if (keyByte.length % base != 0) {
                int groups = keyByte.length / base + 1;
                byte[] temp = new byte[groups * base];
                Arrays.fill(temp, (byte) 0);
                System.arraycopy(keyByte, 0, temp, 0, keyByte.length);
                keyByte = temp;
            }
            // 初始化
            Security.addProvider(new BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding","BC");
            SecretKeySpec spec = new SecretKeySpec(keyByte, "AES");
            AlgorithmParameters parameters = AlgorithmParameters.getInstance("AES");
            parameters.init(new IvParameterSpec(ivByte));
            cipher.init(Cipher.DECRYPT_MODE, spec, parameters);// 初始化
            byte[] resultByte = cipher.doFinal(dataByte);
            if (null != resultByte && resultByte.length > 0) {
                String result = new String(resultByte, StandardCharsets.UTF_8);
                return JSONObject.fromObject(result);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public static void main(String[] args) {
        String encryptedData = "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";
        String sessionKey= "SbPsjLnBGL9wZv0X0wgSaQ==";
        String iv = "cE7M8d74IDot5dnBYBvG6w==";
        System.out.println( getUserInfo(encryptedData,  sessionKey, iv));
    }
}